Light-projecting device.



L. FRASSIER. LIGHT PROJEOTING DEVICE. APPLICATION FILED 00114, 1912.

2 SHEETS-SHEET 1.

Pay]

$ M, LEM 4 v g? Patented June 23, 1914.

L. FRASSIER. LIGHT PROJEGTING DEVICE.

APPLIGATION FILED 00114, 1912.

1,1 01, 1 72, Patented June 23, 1914.

2 SHEETS-SHEBT 2.

STATES PATENT OFFICE.

LEON FBASSIEB, QE PA'RIS,

LIGHT-PBOJECTING DEVICE.

Specification of Letters Patent.

Application'filed October 1A. 1912. Serial No. 725,586.

To all whom {it may concern:

Be it known. t-h t I, LEON FRASSIER, a citizen of the Republic of France, residing in Paris, France, have invented certain new and useful Improvements in Light-Projecting. Devices, of which the following is a specification;

This invention. relates to light projecting apparatus. in which the source of light involves considerable radiation of heat, and p r icularly --'to apparatus for projecting vie'wsor images upon'a screen, and has for its object .to provide means whereby the heatlradiatedufrom. the source of light may be so dissipated or dlsposed .of as to avoid undue heatingof certain portions of the apparatus, such as the usual film employed in. displaying kinematograph pictures, so

avoiding accidents due tothe film or its asso-;

ciated: parts catching fire, at the same time.

lightrays emitted by an arc lamp 01' itsequivalent through or upon: the film or image to be depicted upon the field or screen are interposed between the source of light and a watertank with the object of reducing the intensity of the heat rays emitted. by the source of light and=to thus reducethe risk .of tfire' due to :the ver-heating of the kinematograph film. But, this position of the optical {condenser of theluminous rays between the source of light and the water tank is quite unsuitable when the primary object to bet-achieved is and concentrates the heat rays emitted by the light rdi-rectly upon the water tank, with the result that the water in the tank is heated more under these circumstances than would be. the case if the heat rays were considered] owing 1 to the: fact that the condensing lens collects located the distribution of "the v light is not uniform over the entire surface-of the image orfilm to be illuminated and experience has shown that with a weak l ght a reflection of the points of the carhens, in .cases inwhich an arc'lamp is employed, is visible upon the screen in the form of a dark spot which is very prejudi cial to the quality and tone of the image or picture projected. All these-dangers and disadvantages are overcome by the arran ement forming the subject matter of" e present invention, the primary feature of which consists in causin the rays emitted from the source of lig t to traverse the mass of water before reaching the-condenser, a compound lens concentrating-the luminous rays on the images or film carrying the device, to be projected. The heat rays emanating from thesource of \light'ane absorbed and dissipated. therefore before passing through. the condenser and are thu rincapable. of over-heating the filmas :it. is wound from one reel to the others The-temperature of the luminous beam. when it reaches the film "under these conditionsris such that the mechanism for rotating-the film from one reel to the otherunay be stopped if clesired, thus allowing the same picture of the -film tov remain in rfrontof the projectinglens or aperture without danger of setting fire to the =film as isnoW so common. Apart however from demonstrating the cooling-effect of the improved arrangement, this is particularly convenient when demonstrating scientific pictures-for instruction purposes where it may bedesirable to have the same view or image dopicted upon the screen for a considerable time, as'in schools or lecture-halls for instance. The arrangement of the optical condensing lens on the front of thewater tankla'lso results in permitting the-source'of light to be brought considerably nearer to the tank because the heat of the rays is im' mediately removed; by the water through \vhichthese. rays pass-consequently, the

illuminating power of the luminous body is ing atsiugletlens interposed. between the Patented June 23, 1914.

source of light and the back of the cooling tank which efiects this concentration of the luminous rays without unduly heating the water in the tank. In a preferred form of the invention this single lens for concentrating th luminous rays is surrounded by.

a small tank containing water which takes up the greater portion of the heat which the luminous rays concentrated by this lens carry with them. this small tank being connected to the large water tank referredto above. The lens cooled in this manner is protected from fracture by the heat but is furthermore arranged in an open chamher which is traversed by a current of air which prevents the formation of steam which would be produced if the lens were placed in a closed receptacle.

Although the water in the tank is only slightly heated under the conditions mentioned above, regardless of whether a simple condensing lens be employed-located between the water tank and the source of light. it is advisable to maintain as complete and continual circulation and cooling of this water as possible so that the same water may be employed for a considerable time.

The invention is illustrated in the accompanying drawings in which- Figure 1 is a view in front elevation partly sectional of a light projecting device embodying the invention. Fig. 2 is a longitudinal sectional view on the line M M of Fig. 1.

Referring now to the drawings, the invention is shown as comprising a tank for circulating water arranged in front of the source of light such as an arclamp F which is intended to illuminate the film carrying the image or picture to be projected. The optical condenser K is located'on the front of the tank A, that is to say on the opposite side of the tank to that on which the source of light F is located. The heat rays emitted by the luminous source are absorbed by the water in the tank A before reaching the condenser. This water is kept in continuous movement and cools in the following manner. -Adjacent to each lateral face of the tank a serpentine tube B is provided. the lower extremity of each of which communicates with the base of the tank by means of an internally projecting pipe a provided at its upper extremity within the tank with a valve 7) constituted by a bronze ball for example; eachserpent-ine B communicates at its upper end with a receiver 0, these receivers. the tank A and the serpentine tubes B being filled with water. From above the tank A two vertically extending tubes 0 project and terminate in an enlargement or chamber 03 located on a level somewhat higher than that of the receiver C, the base of each chamber a? constituting the seat for a ball valve 6. Each chamber d communicates on the one hand with a small expansible reservoir 7" located above it, the reservoirs f being in communication with the atmosphere through a suitable pipe or passage The chambers 07 also communicate through openings formed in the walls thereof with the serpentine tube D the lower convolution of which abuts against a vertical tube it arranged within the interior of the reservoir C and the upper end of which is provided with a valve i constituted by a ball. The two receivers C are connected at the top by a tube E, which is also connected intermediate its extremities by a vertical tube G' to the compression chamber of a pump P The'pump P comprises a plunger fl provided with a ball valve 0, the stem of the plunger terminating in an enlarged portion in constituting the pump handle.

The circulation of the water in the tank is produced in the following manner.Whi-le the film is being transferred from one film carrier tothe other the tank A, the receivers O and the serpentine tubes B and D being filled with water, the luminous rays from the source of light first traverse the water in the tank A, imparting their heat to the water contained in the tank A. The water which is at a higher temperature in the upper portion of the tank rises in the vertical tubes 0, raises the ball valves 6, passes into the chambers 03, descends again into the serpentine tubes D, risesagain in the vertical tubes It, raises the 'ball valves 2', passes into the receivers C and from thence passes through the serpentine tubes B and thepipes' a to the bottom of thetank A. This automatic thermo siphon circulation of the water. as it becomes heated, may be accelerated by amechanical device such for instance as that constituted by the pump P in the following manner.The plunger H of this pump being at the end of its upward stroke, thewater in the tank A. the serpen-I tine tubes B, D and the reservoirs C is at atmospheric pressure, since these elements of the coolingsystem are in communication withthe atmosphere through the passages g g on the one hand and also through the orifices uncovered by the valve 0 of the pump plunger H when the valve is in its normal position. When the pump plunger H is forced downward, the valve 0 is moved by the pressure within the pump chamber to cutofi communication between the interior of this chamber and the atmosphere, and the air thus compressed is forced through the pipe G and the pipes E, E into the inte riorof the reservoirs C. The valves 1' being by reason of their weight and the pressure thus produced, maintained on their respective seats, the water from the receivers C is forced toward the serpentine tubes B thus passing into 'the tank A, the heated water in the upper portion of which is forced into tioned as to permitfof a ready evacuation of the. air therein contained when the pump P is operated.

When the pump plunger H is released the water contained in the reservoirs f redescends, owing to the difference in the level between'that of the serpentine tubes ,D and, these reservoirs,the water passing into'the receivers C throughthe pi s h into the serpentine tubes B B and mm thence to thetank A.

It should be noted that the water in the expansible reservoirs f f cannot pass directly into the tankA when the pump plunger isreleased. owing to the pressure on the non-return ball valves ec whlch under these circumstances cuts 2 oil communication be'-. tween the tank A andthe chambers (I through the pipes cconnecting the latter. 7

The'compound condensing lens mounted on the front of the wiater ta-nk A is constituted by two plano-convex lenses 0, 0 arranged} with their conv sides adjacent to eachother and secured to a 'fix'e'd lens-carrier K by screws or-the' like and mounted in anannular member I attached to the wall of the water tank A. The annular member I also supportsia glass-disk m interposed betweenthe plane-convex lens and the water within thetank A'f-f A similar'annular member is-provided on the opposite side of the water. tank for supporting a corresponding glassdisk m permittingthe passageof the luminous ra s across the watertank.

The "simp e condensing lens which is located betweeii thewater tank A and the source of light employed when the tank is located at some distance from the source of light as'whe'n projecting images or pictures at a considerable distance. is constituted by a single lens J of lano-convex form and carried hy-an annular member Q supported in a removable frame R which may be secured by screws or the like to the annular memberl. 'This single lens J is cooled on the one hand by the'water in the tank. and on the other hand by the water contained in a small auxiliary tank constituted'by the lens carrying frame R and two glass disks S, S, the small auxiliary tank communicating at the top and bottom with the tank A through two pipes p, p leading to passages q qm the wall of the tank A.

Furthermore the interior of the mount carrying this lens is placed in free comnuinication with the atmosphere by means of a number of holes r thus preventing the formotion of steam upon the faces of the lens. This additional single lens enables the light rays omitted to be utilized with good effect even when the lens is located at some considerable distance from the source of light and it also prevents the disfigurement of the pictures above referred to in which a refiection of the carbon points is transmitted upon the screen owing to a weak light.

It will be understood that the invention is not limited-to the particular construction and arrangement of the parts herein described and illustrated as various modifications-may be made without exceeding the scope of the invention.

I claim as my invention-- 1 -In a kinematographic projecting apparatus, the combination of a source of light, a condensing lens, and a water-tank between said lens and source of light, adapted to absorb heat from rays emitted by said source of light, which pass on to said lens theretlirough. said tank having a circulatory thermo-siphon cooling system in communication therewith, adapted to radiate heat to the atmosphere and mechanical means for producing a forced circulation through said tank andfcooling system for accelerating the circulation of the water therein when necessary.

2. In a kinematographic projecting apparatus, the combination of a source oflight,

a condensing lens, and a water-tank between said lens and source of light. adapted to absorb heat from rays emitted by said source of light, which pass on to said lens therethrough. said tank having a circulatory thermo-siphon cooling system in communication therewith, adapted to radiate heat to the atmosphere,- and an air pump for producing a forcedcirculation through said tank and cooling system for accelerating cooling of the water therein when necessary.

3. In a kinematographic projecting apparatus. the. combination of a source of light. a condcnsinglens. and a water-tank between said lens and source of light. adapted to absorb heat from rays emitted by said source of light, which pass on to said lens thercthrough. said tank having a circulatory thermo-siphon cooling system in communication therewith adapted to radiate heat to the atmosphere. and valves in said system for preventing back pressure in said circulatory svstem.

4. In a kinematographic projecting apparatus. the combination of a source of light, a condensing lens. and a water-tank between said lens and source of light adapted to absorb heat from rays emitted by said source of light which pass on to said lens therethrough, said tank having a circulatory thermo'siphon cooling s stem in communication therewith adapte to radiate heat to the atmosphere, mechanical means for producing a forced circulation through said tank and cooling system for accelerating the cooling of the water therein when necealry,

and valvesin said system for preventing back pressure in said circulatory system.

5. in a kinematographic pro ecting apparatus, the combination of a source of light, a main condensing lens, a water-tank interposed between said source of light and said main ctni'densing' lens, an auxiliary condensing lens, and an auxiliary water-tank inter,- posed between said source of light and said auxiliary lens, and a circulatory thermosiphon cooling system in communication with said tank, said water tanks being adapted to absorb heat from the rays emitted from saidsource of light which pass on through said tanks to said condensers, the rays which pass through said tank which is in front of said auxiliary lens passing through said auxiliary tank without previous concentration. said auxiliary lens being located in a chamber adapted to have a circulation of air therethrough on both sides of said lens.

6. A device for use in cooling the rays from a source of light of a kinematographic projection apparatus, comprising a water tank of relatively small dimensions having a window therethrough for the passage of rays from the source of light, and heat radiating thermo-circulatory means, said means being connected to said tank and having all parts out of the path of the rays through said window.

7. A self-contained device for use in cooling the rays from a source of light in a kinematographic projection apparatus, comprising a water tank of relatively small dimensions, having a window therethrough for the passage of rays from the source of light, and a heat radiating thermo-circulatory means, said means comprising. coiled pipe in contact with the air, connected to the said tank, and having all parts out ofthe path of the rays through said window.

8. A self-contained device for use in cooling the rays from a source of light of a kinematographic projection apparatus, comprising a water tank of relatlvel small dimensions, having a window theret X'Olgh for the passage of rays from the source 0 light, a condensing lens on the side of said tank ad'acent to the source of light, and heat radiating thermo-circulatory means, said means comprising coiled pipe in contact with the air, connected to sai tank, and having all arts out of the path of the rays through sai window.

9. A self-contained device for use in cooling the rays from a source of light of a m ta lLu'Q lrinematographic projection apparatus, comprising a water tank of relatively small dimensions, having a window therethrough for the passage of rays from the source of light, a condensing lens on the side of said tank adjacent to the'source of light, said lens being exposed to air circulation on both sides thereof, and heat radiating thermo-circulatory' means, said means comprising coiled pipe in contact'with the air, connected to said tank, and having all parts out of the path of the rays through said window.

10. A elf-contained device for use in cooling the rays from a source of light in a kinematographic projection apparatus, comprising a water tankof relatively small dimensions, having a window therethrough for the passage of rays from a source of light, and heat'radiating thermo-circulatory means, said mean comprisingcoiled pipe in contact with the air, connected to said tank, and having all parts out of the path of the rays through said window, and a small tank in the circulatory system between parts of said coiledipe.

11. A set -contained device for useincooling the rays from a source of light in a kinematographic projection apparatus, comprising awater tank of relatively small dimensions having windows in the side walls thereof for the passage of rays from the source-of light, and heat radiating thermocirculatory means, said means comprising coiled pipe in contact with the air, connected to said tank, and having all parts out of the path ofthe rays through said window.

12. A self-contained device for use in cooling the ra- Vs from a source of light in a kinematographic projection apparatus, com rising a main water tank of relativel sma dimensions, having a window theret irough for the assage of rays from the source of light, a condensing lens on the side of said tank adjacent the source of light, and an auxiliary water tank in rear of said lens, and heat radiating thermocircu'latory means, said means comprising a coiled pipe in contact with the 1111', connected to said main tank, and having all parts out of the path of the rays through said window.

In witness whereof, I have hereunto signed my name in thepresence of two subscribing witnesses.

LEON FRASSIER. Witnesses Hanson C. Coxn, Rune BARDY. 

